1. Field of the Invention
The present invention generally relates to a coated fabric of a polyester fiber which does not exhibit any staining due to dye migration and a method for preparation thereof.
2. Description of the Relevant Art
As coated fabrics are widely used nowadays, woven and knitted fabrics have nylon fibers as the main components and are, for example, treated with such treatments as repellent and waterproof, water-vapor permeable and repellent, breathable, flame-proof and melt-proof coatings.
Recently, however, differences in prices between nylon fibers and polyester fibers have remarkably increased that development on coating treatments of polyester fibers are being actively carried out. Polyester fibers have such superior characteristics as in dimensional stability, strength, light resistance and diversity of the raw material as compared to nylon fibers.
However, the coated fabrics of polyester fiber have such a fatal defect that the dye in the polyester fiber migrates to the coated film so that the coated film of the product having the base fabric of which is dyed and the other coated film which is brought into contact therewith through the film faces thereof are stained. In other words, in the case of dyeing the polyester fiber with a dispersed dye, polyester fiber does not combine chemically with the dye, for example, in contrast with the dyeing of nylon with an acid dye and in addition, the dispersed dye has good solubility in and affinity with organic solvents and synthetic resins so that the dye molecules in the fiber could easily migrate to the coated film layer.
Therefore, when coated faces of different colors are brought into contact with each other, staining consequently occurs. Various investigations have taken place in order to solve this problem, but no satisfactory or perfect solution has yet been found, and thus, a dyed product of the coated fabric of a polyester fiber has not been put to practical use.
So far, in both Japanese Patent Laid-Open Publication No. 4873/1983, and Japanese Patent Publication No. 53632/1987, methods which have quite different purposes from that of the present invention have been proposed. It is proposed in these publications that fiber structures are to be treated by providing a water repellant having a perfluoroalkyl group to a fiber structure on which a polyurethane resin film containing porous particles wherein SiO.sub.2 was the main component.
However, the methods disclosed in the publications attempt to obtain a waterproof fabric exhibiting both breathable and water-vapor permeable characteristics by making fine pores of particles incorporated in a polyurethane resin for paths for air and water-vapor, but no suggestion is made on a coating film which can prevent staining caused by a dispersed dye.